import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		double g = sc.nextInt();
		int v = sc.nextInt();
	    System.out.println(java.math.BigDecimal.valueOf(n / 5 * g / v).toPlainString());
	}
}